HomeMy WebLinkAboutGreat Meadow Study Comm 1971 Rpt June 14, 1971
The Great Meadow Hydrology and Land Use Study
The Arlington-Lexington Great Meadow Study Committee announces the
completion of the hydrology and land use study of this area. The,results
of the study are presented in detail and indicate the importance of keeping
the Great Meadow available to Arlington and Lexington as a natural open
space area with some emphasis on flood control. Copies of the final report
have been presented to the Boards of Selectmen of both towns. Copies have
also been given to the Town Managers and town agencies concerned with land
use: including Town Planners, the Town Engineers, the Conservation
Commissions and the Finance Committees. Several copies will be available
in the reference room of Cary Memorial Library in Lexington and Robbins
Library in Arlington.
Camp, Dresser & McKee, the consulting engineers, have compiled a summary
with recommendations for possible land use. Included in the body of the
report are graphs, charts, and maps, as well as an appendices of the ecological
study, subsoil investigation and legislation relating to the Great Meadows
beginning with the Acts of the General Court, 1871
Cooperation and assistance was received from officials and employees of the
two towns. The Committee is particularly appreciative and indebted to those
citizens of Lexington who volunteered to supervise the water gages at key
points in the hydrology study. Arlington members are Mr. Aubrey C. Tobey,
Dr. Herbert M. Meyer, and Mr. John Ashton, Lexington members are
Mrs. Angela E. Frick, Dr. Howard M. Kassler, and Dr. Manfred P. Friedman.
This report is only the beginning. The Joint Committee will submit its
appraisal and recommendations for implementation to the Boards of Selectmen
for their consideration and action These end use recommendations based on
the findings of Camp, Dresser & McKee will be ordered to reflect the under-
stood needs and cooperative potential for sustained support by the two towns.
Meanwhile, the report should provide fundamental and valuable information for
determining use of land contiguous to and within the Great Meadow watershed.
JOINT ARLINGTON - LEXINGTON GREAT MEADOW COMMITTEE
THOMAS R CAMP EMERITUS
HERMAN G DRESSER EMERITUS
JACK E MCKEE
CAMP , DRESSER Eti McKEE JOSEPH LAWLER
ROLAND S.BURLINGAME
DARRELL A.ROOT
CONSULTING ENGINEERS JOSEPHE HENEY
ROBERTC MARINI
CHARLES A PARTHUM
WATER RESOURCES DRAINAGE AND FLOOD CONTROL DONALDE CULLIVAN
WILLIAM C FREEMAN
WATER SUPPLY AND TREATMENT WATER AND AIR POLLUTION PAULW PRENDIVILLE =
SEWERAGE AND SEWAGE TREATMENT REFUSE DISPOSAL ASSOCIATES
INDUSTRIAL WASTE TREATMENT RESEARCH AND DEVELOPMENT ROBERTH CULVER
FRANK L HEANEY '..
REPORTS DESIGN • SERVICES DURING CONSTRUCTION R ERNESTLEFFEL C
FRANK T SMITH,JR.
NATHANIEL H CALDER
December 8, 1970 JOSEPHC KNOX
R DENIS C.LLOYD
JAMES ARBUTHNOT
RICHARD H ESTES
DAVID R HORSEFIELD
ROBERT F PELLETIER
ELWOOD C.RICHARDSON
WIL
TRAQUA
Mr. Aubrey C. Tobey, Chairman RICHARD
C WOODWIR
RICHARD L WOODWARD
Joint Arlington-Lexington JOSEPH B HANLON
ADMINISTRATIVE MANAGER
Great Meadows Study Committee ROBERT JEWETT
Arlington, Massachusetts 02174
Report on Hydrology and
Land Use of the Great
Meadows
CDM 489-1
Dear Mr. Tobey:
In compliance with the terms of our contract dated September 8, 1969,
we have made an engineering investigation of the hydrology and land
use of the Great Meadows and its watershed. 1
The results of our studies are presented in detail in the following
report, including recommendations for land use of the Great Meadows
proper and of the watershed that constitutes the headwaters of Mill
Brook, in order to alleviate the flooding potential in the area. The
more significant recommendations are summarized below.
RECOMMENDATIONS
1. Only very limited development should be permitted on those areas
of the Munroe Brook watershed which have flood retardation valve.
2. Use of the Arlington Reservoir as a flood control structure should
be considered, even at the expense of sacrificing recreational uses
to an increasing degree.
3. The Great Meadows area should be kept for open space use, it should
also be used for flood retardation purposes for short periods of
time.
4. The capacity of the Mill Brook channel downstream of Arlington Reser-
voir should be investigated and the necessary corrective measures
accomplished to minimize flood damages during major storms.
5. The Great Meadows area should be subjected to land use criteria that
are of such a type and extent that they.
D ES
ONE CENTER PLAZA BOSTON MASS. 02108 TEL 617 742 51 51 CABLE CAM R
CAMP, DRESSER & MCKEE
Mr. A.C. Tobey -2-
December 8, 1970
ti - are not objectionable to surrounding areas due to noise, smoke,
dust or odors and do not pollute the land, air, water, or en-
vironment;
- are compatible with the surrounding area and provide for the
needs of both Arlington and Lexington giving the greatest ben-
efit with the least cost;
- do not increase the flood potential either downstream or up-
stream and do not change the water table to deleteriously af-
fect surrounding structures or the ecologic environment.
- aid in the prevention of floods, pollution and the depletion
of the natural resources.
6. The Great Meadows should be maintained as a natural wildlife preserve
and such flora and fauna as presently exist should be preserved.
7. The contamination of Munroe Brook and the Arlington Reservoir by seep-
age from the Arlington Sanitary Landfill area, should be eliminated
by conveying the contaminated seepage into the municipal sewer line
SUMMARY
Background
The Great Meadows area consists of about 183 acres of land owned by the
Town of Arlington (although entirely located in the Town of Lexington) ,
approximately one-half mile northwest of the Arlington-Lexington bound-
ary line and between Lowell Street, Maple Street and the Boston and
Maine railroad embankment. The land was acquired by the Town of Arling-
ton in 1872 in order to provide adequate water supply to the town. When
the Arlington Reservoir was built, about 175 acres of the Great Meadows
were taken to provide a storage basin in which the surplus waters of
Munroe and Fessenden Brooks could be stored in the spring and used to
supplement the storage at Arlington Reservoir.
Later on, to improve the quality and quantity of the Arlington water sup-
ply, 25 tubular wells were driven in a bank of coarse gravel at the edge
of the Great Meadows near the East Lexington Railroad Station. A pumping
station was built, with a nominal capacity of 500 gallons per minute.
Water was pumped into a stand pipe in the center of the Park at the top
of Arlington Heights.
Since January 1899, when Arlington was admitted to the Metropolitan Dis-
trict Commission Water Supply, the storage in the Great Meadows area and
the pumping from the wells have been discontinued. In later years, the
Great Meadows area was drained for mosquito control.
CAMP, DRESSER & McKEE
Mr. A.C. Tobey -3-
December 8, 1970
While both towns have been concerned about the use of this land, for many
years it has remained idle and of little use to either town except for
the abutters. In 1965, each town appointed a Great Meadows Study Committee
to study the potential of this area for use beneficial to both towns taking
into consideration its development in terms of flood control as well as the
recreational and conservation needs of both towns.
Hydrology of the Great Meadows Area
Since there were no runoff records in the area under study, gages were in-
stalled in Munroe Brook at Maple Street and Lillian Road, in Sickle Brook
at Massachusetts Avenue and in Mill Brook at the outlet from Arlington Reser-
voir. Two raingages were installed, one at 17 Smith Avenue, Lexington and
one at 3 Rolling Lane, Burlington. The intention was to obtain at least one
year of hydrologic records. The gaging program started on November 1, 1969
and ended on October 31, 1970.
Discharge measurements were made during the wet and dry seasons to develop
stage-discharge relationships of stream flow and to compare the runoff with
the precipitation in the area.
The climate of the study area is characteristic of the northeastern part of
Massachusetts, with fairly uniform monthly precipitation, warm summers and
cold winters. The mean annual temperature in Arlington (1942-1950) is 51.4°F.
The average rainfall in the Arlington-Lexington area is 46.16 inches, (1942-
1956) as compared to 42.40 inches in Boston, 45.52 inches for Spot Pond in
Stoneham and 40.94 inches for Reading, Massachusetts. The total rainfall
during the study period (Nov. 1969-Oct. 1970) at the Lexington raingage was
37.95 inches and at the Burlington raingage 51.04 inches. December was the
wettest month during the study period; total precipitation was 13.87 inches
at Lexington, 10.32 inches at Burlington and 10.55 inches at Reading. At
the Reading station, December, 1969 had the highest precipitation for this
month since observations started in 1899, exceeding the previous record of
8.24 inches set in 1937.
The total runoff during the study period at the Arlington Reservoir gaging
station was 35.43 inches and at Lillian Road it was 35.57 inches. The high
ratio of the rainfall to the runoff for the year is due to the fact that most
of the runoff occurred during the wet winter months, when the ground conditions
produced high runoff coefficients. Under normal conditions, and with a poten-
tial evapotranspiration of 14.0 inches, there should be enough water for basin
recharge.
Flood Problems
Based on the hydrologic characteristics of the watershed we have estimated
the peak flows that might occur in the Munroe Brook and the Sickle Brook water-
sheds. From our estimates we have concluded that there is definite flood potential
Mr. A.C. Tobey -4- CAMP, DRESSER & McKEE
December 8, 1970
in both watersheds that can be aggravated by developments in the areas that
are acting at the present time as flood retardation zones. In Munroe Brook
there are at the present time some developments taking place in the wet lands
which if left in their present state could otherwise reduce the magnitude of
peak flows to be expected downstream from Lillian Road. If the available
land in this watershed is developed from its former natural condition to a
highly developed area - such as apartments - the magnitude of the peak flows
to be expected from a 10-yr. frequency storm might change to those expected
from a 100-yr. frequency storm.
The same flooding conditions are expected to occur in Sickle Brook if the
watershed and the Great Meadows are developed extensively. If no changes
are made in the status of the Great Meadows, development of other vacant
areas in the watershed alone can increase the magnitude of the peak flows
from those expected in a 10-yr. frequency storm to those expected from a 15-yr.
frequency storm. Substantial increases are to be expected if the Great Meadows
is developed to a type of development similar to suburban housing. If a large
impervious surface is introduced in the Great Meadows, as a parking lot for
example, the flood potential downstream would become even more critical than
it already is.
An investigation of the channel capacities of Munroe Brook and Sickle Brook
discloses that there are some areas that presently can be flooded at peak
flow conditions higher than a 10-yr. flood. In Munroe Brook the channel ca-
pacity, especially between Lillian Road and the reservoir, is somewhat con-
trolled by the operating levels of Arlington Reservoir. Upstream of Lillian
Road a narrow flood plain dampens the effect of peak discharges, the same as
the marshy area north of Maple Street. Any encroachments on the flood plain
or the flat swampy areas adjacent to Munroe Brook and Fessenden Brook will,
as discussed above, increase the peak flows from the watershed into Arlington
Reservoir and consequently in Mill Brook.
The Sickle Brook channel from Fottler Avenue to the Arlington Reservoir is
capable of handling high frequency flows within the main channel. Flooding,
if any, will be restricted to certain areas of the Great Meadows, which na-
turally acts as a flood retarding area. The elimination of this area by de-
velopments that would alter its retardation value will increase the flood
potential downstream.
We are of the opinion that Mill Brook downstream from Arlington Reservoir pre-
sents a very serious flooding problem, since many developments have been con-
structed in Arlington adjacent to the banks and the channel appears to be con-
stricted by some undersized structures. It seems probable that extensive
flooding might occur from a 25-year storm.
Flood Protection
Since considerable development is taking place in the Munroe Brook watershed
and more available land will be developed in the future, serious consideration
should be given to the flooding potentials in the Munroe Brook drainage system.
CAMP, DRESSER & MCKEE
Mr, A.C. Tobey -5-
December 8, 1970
Since flood-producing storms can be expected to occur at any time during
the year, the possibility of using the Arlington Reservoir as a flood
control structure at the cost of temporarily sacrificing some of its rec-
reational uses should be considered.The present practice of lowering the
reservoir water level just prior to an intense summer storm or prior to
a hurricane threat should be continued.
The peak flows in Mill Brook downstream of Arlington Reservoir are the
result of the combination of peak flows from Munroe Brook and Sickle
Brook. Some dampening effect is obtained in Arlington Reservoir by
keeping its level as low as possible. An additional degree of protec-
tion from flood hazards could be obtained if a retardation structure
could be introduced in the system. It appears feasible to obtain a
substantial dampening effect of peak flows in Sickle Brook if a flood
retardation reservoir is created by building a low dam at Fottler Ave-
nue. If the full capacity of the Meadows is utilized, we have estima-
ted that a 10-yr. flood (150 cubic feet per sec - cfs) would be dampened
to about 30 cfs. This reservoir would be drained immediately after the
flows have reached a reasonable level in Mill Brook, and would be empty
most of the time. We are of the opinion that such a flood retardation
reservoir would not interfere with an open space use of the Great Meadows.
Groundwater
Based on the subsoil investigations made in the Great Meadows area, we
have estimated that the hydraulically connected kames and outwash deposits
that constitute the aquifer have a capacity of approximately 300,000,000
cubic feet. The safe yield of such an aquifer, based on the storage-yield
relationship of water supply watersheds, has been estimated to be in the
approximate range of 0.75 to 0.90 million gallons per day (mgd). Such a
draft, even if continuous during drought periods, would not seriously de-
plete the groundwater level in the Great Meadows and the groundwater stor-
age would be replenished annually by natural recharge.
While 0.75 to 0.90 mgd. is insignificant with relation to the present or
projected municipal water supply needs of either Arlington or Lexington,
even for emergency purposes, it would be more than ample for irrigation
of an open type development such as a park or golf course which might be
built in the Great Meadows.
Water Uses
We have studied the possibility of augmenting the Mill Brook flows using
waters from the Arlington Reservoir, Sickle Brook and groundwater from
Great Meadows, to alleviate any pollution problems in Mill Brook. As
will be discussed later under "Ecology", the major sources of pollution
in the watershed can be controlled by properly connecting those sources
to the Metropolitan District Commission sewers. Therefore, we are of
Mr. A. C. Tobey -6- CAMP, DRESSER & McKEE
December 8, 1970
the opinion that no substantial quantities of water from the watershed
need to be devoted to pollution control.
The sustained use of water from the study area for emergency municipal
supply requires the addition of storage to the system. We estimate
that to supply in an emergency about 21,500 people it would be neces-
sary to build a reservior of about 20 million cubic feet in Great
Meadows, and a 44 million cubic feet reservoir if the required with-
drawal rate is increased to supply about 30,000 people. Such reser-
voirs are ruled out by the necessity of building expensive structures
to protect the railroad embankment and existing developments. Further-
more, the existence of such reservoirs would interfere with any type
of open space development that could be built in the area. Since pro-
visions would have to be made to treat the supplied waters to some ex-
tent, we are of the opinion that such use is not profitable for either
one of the municipalities involved.
Based on the hydrological findings, we recommend that the following
steps should be taken to alleviate the flood problems of the study
area:
1. Permit only very limited development in the areas of Munroe
Brook that have a flood retardation value.
2. Consider the possibility of using the Arlington Reservoir as
a flood control structure, sacrificing recreational uses if
necessary.
3. Keep the Great Meadows area as an open space use and plan
on using the area for flood retardation purposes for short
periods of time. It should be kept in mind that dense vege-
tation in the slopes of the Great Meadows introduces a time-
lag effect that increases the retardation capacity.
4. Investigate the existing capacities of the Mill Brook
channel downstream of Arlington Reservoir and take the neces-
sary corrective measures if the channel and structures prove
to be insufficient.
It seems advisable also to continue reading some of the staff gages,
especially the one at Arlington Reservoir, to gather a long term rec-
ord of hydrological information that will prove to be very valuable
for future studies and planning of the area.
Land Use
If physical limitations and the effect of the ecology and the surrounding
areas is neglected, it would be possible to develop the Great Meadows
area for any number of uses ranging from highly inadvisable extensive
use (residential, commercial, light industrial, public buildings) to
the more preferred open area use (parks, playfields, golf course, wild-
life and vegetation natural conservation area).
Mr A C Tobey -7- CAMP, DRESSER 8c McKEE
December 8, 1970
Major constraints on the use of the Great Meadows area are the soil con-
ditions in the large flat section underlain with peat and the need to
alleviate flood potential downstream. The natural environment of the
area is considered to have intrinsic value as a natural wildlife preserve
and as an outdoor ecologic classroom.
Many previous studies and reports originated locally by the regional
planning agency (MAPC), the State Department of Natural Resources, 'the
Metropolitan District Commission, the State Department of Public Works
and the Massachusetts Bay Transit Authority have had reference to the
use of the Great Meadows area. For the most part, these references re-
commended the retention of the area for an open space use as a natural
environment and golf course. Other references such as the proposed
Route 3 and mass transit proposals would have developed the Great
Meadows area with large areas of pavement and structures. At the pre'-'
sent time, the mass transit terminus and Route 3 have been shelved and
are not considered likely.
The following land use selection criteria was developed for the use
of the Great Meadows:
The uses of the land shall be of a type and extent that they:
-are compatible with the surrounding area in terms of safety and
health;
-are not objectionable to surrounding areas due to noise, smoke,
dust or odors or pollute the land, air, water, or environment;
-provide for the needs of both communities (Arlington and Lexing-
ton) , giving the greatest benefit with the least cost;
-do not increase the flood potential downstream or upstream;
-do not change the water table to the extent that deleteriously
affects surrounding structures or the ecologic environment
(plants, animals, or other desirable living creatures) ;
-aid in preventing safety hazards such as floods, pollution, and
depletion of natural resources.
Based on the findings and implications of the soils, hydrologic and
ecologic studies we found that the most critical need was for flood
protection. By constructing a small dam at Fottler Avenue, a flood
storage reservoir can be created in the Great Meadows area which would
dampen peak flows and alleviate to a considerable degree potential
flooding downstream. Any development which would add fill in the low
sections or increase the runoff in the Great Meadows area would reduce
the amount of protection that could be afforded by such a storage and
reservoir. The use of the area for certain open space uses such as
athletic fields or a golf course would require some filling in part of
the area.
CAMP, DRESSER & MCKEE
Mr. A. C. Tobey -8-
December 8, 1970
We therefore recommend that the preferred land use of the Great Meadows
area be retention in its natural state, a small dam to be constructed
at Fottler Avenue on Sickle Brook to create a flood storage reservoir
and the use of the Great Meadows be limited to ecological education,
passive and limited active recreation (such as walking, picnicking, ice
skating) . Appropriate legislative action should be sought to protect
this land for conservation purposes so that future pressures for more
intensive development can be combatted.
It is strongly recommended that no extensive development such as hous-
ing, industry, business, transit terminus or public buildings which
would require structures and extensive paved areas be permitted in the
Great Meadows area.
If downstream flood potential can be alleviated significantly by some
other means such as utilizing the Arlington Reservoir for flood control
all year and temporarily curtailing its recreation use, it may be possible
to sacrifice some of the flood storage capacity of the Great Meadows and
permit a combination of uses therein including a natural undeveloped area
and a low intensity use such as a golf course on part of the area. It
should be kept in mind, however, that additional development in the
watershed outside of the Great Meadows is expected, and the flood pro-
tection need is expected to increase and there are no flood retarding
opportunities equal to the Great Meadows available.
In regards to areas outside of the Great Meadows it is recommended that
development of the remaining vacant and wetland areas along the Munroe
Brook be closely followed and reviewed. Any proposals that would re-
duce the wetlands further and/or increase peak runoff flows should
also include flood retardation measures such as ponds, lagoons or other
appropriate devices. Any future developments in the Mill Brook water-
shed should avoid concentration of large pavement, roof or sloped areas
which would increase or hasten runoff.
Ecology of the Great Meadows
While the Great Meadows does not support an abundance of wildlife, the
area, nevertheless, has a sufficient diversity of flora and fauna to
justify its preservation.
Aquatic and terrestrial forms are found in an ecological pattern which
corresponds to the hydrological conditions present within this natural
area. Aquatic and semi-aquatic plants and animals inhabit the wet low-
lands while corresponding forms of wildlife can be found throughout the
grassy dry mesic zone and the high ridge of the xeric zone. The Great
Meadows, therefore, represents a typical senile peat bog whose moisture
content is of significance throughout the year. In its original state,
the watershed comprised of much more wetlands similar to the Great
Meadows in which considerable wildlife flourished. The gradual filling
in of the wetlands along Munroe, Fessenden and Sickle Brooks has de-
creased the water-holding capacity of these flood plains and increased
CAMP, DRESSER & McKEE
Mr. A.C. Tobey -9-
December 8, 1970
the rapidity of surface runoff. Correspondingly, the natural habitat
for waterfowl and other marshland species has been depleted.
Based on the data accumulated during this study, it would appear that
continued development of the wetlands adjacent to Munroe and Fessenden
Brooks will only lead to further degradation of the environment. Also,
the destruction of natural forested areas and the filling of wetlands
will increase the threat of flooding along Munroe Brook.
Another serious problem which faces the residents of the Town of Arling-
ton, is the continued contamination of Munroe Brook by the highly pollu-
ted waters of Reeds Brook. This small but highly significant water
course receives the drainage from the Arlington Sanitary Landfill area
above Summer Street. It is doubtful that the seepage of water through
the landfill area can be controlled adequately enough to prevent the
continuous drainage of contaminants into Munroe Brook and the Arling-
ton Heights Reservoir. It would appear that the only corrective meas-
ure available, at present, would be to divert Reeds Brook into the Muni-
cipal sewerline as other means of water processing would not appear to
be economically feasible.
The Arlington Reservoir itself is of significant value, not only as a
water resource, but also as a recreational facility for the Town of
Arlington. The contamination of the Arlington Reservoir by Reeds Brook
is most likely the major cause of the high algae and aquatic weed popu-
lation found present each year. Even with the installation of an aera-
tion device to reduce the chemical and biological oxygen demand, the
water quality of the Reservoir will remain marginal until the up-stream
pollution is abated.
Sickle Brook, which later becomes Mill Brook, is subject to a wide range
of environmental pollution. The water in this stream is gradually de-
graded by sub-division and agricultural enrichment in Lexington, as well
as by combined sewer overflows and chloride/sand deposition in Arlington.
The maintenance of the present boundaries around the Great Meadows and
the prohibition of construction within its confines would appear to be
a vital first step towards the preservation of this area. Dredging
and permanent flooding of the Great Meadows lowlands is not feasible.
Problems of turbidity, dense coloration and aquatic vegetation will
inevitably preclude any apparent recreational advantages.
The utilization of the Great Meadows as a natural wildlife preserve and
as an outdoor classroom has intrinsic values which are considerable in
terms of the environmental quality of both communities.
Geology of the Great Meadows
The subsurface exploration program for the study has included a geo-
logical reconnaissance of the site, plus test borings, rod probings
Mr. A.C. Tobey -10- CAMP, DRESSER & McKEE
December 8, 1970
and test pits. In addition a sample of groundwater was recovered for
chemical analysis, after pumping from a test well. The present topo-
graphic features in the Great Meadows Study Area are all the direct
result of continental glaciation. Most are excellent examples of
glacial landforms. No bedrock was observed during the reconnaissance
or encountered in any of the subsurface explorations. Soil types en-
countered included glacial till and glacial outwash in the periphery
of the Great Meadows, and an accumulation of about 24 feet of peat
underneath the Great Meadows. The Great Meadows is far from ideal in
regard to subsurface and foundation conditions. Due to the presence
of the peat deposits, special construction procedures will be required
for site development and building foundations. These procedures will
add considerably to the cost of development, compared to those at a
site with good bearing soils, and may require a longer than normal con-
struction period. Detailed engineering and economic studies will be
required in order to determine the most satisfactory method of develop-
ing the site. Filling for site development, including athletic fields,
parking lots and roadways, will cause settlements of large magnitude
and long duration. A stabilization program will probably be required
in order to reduce residual settlements after construction to toler-
able values. The stabilization program may require filling, surchar-
ing, the installation of settlement observation devices, and a lengthy
waiting period prior to placing the drainage system and final surfaces.
Consultants
The Land Use section of this Report was developed by our consultants,
John Brown Associates of Boston, Massachusetts. The Ecological Study,
appended to this report, was developed by Jason M Cortell and Associ-
ates of Wellesley Hills, Massachusetts. The subsoil investigations
for the Great Meadows Study were done by Haley and Aldrich of Cambridge,
Massachusetts.
Acknowledgements
We wish to acknowledge with thanks the cooperation and assistance we
received from the members of the Great Meadows Study Committee, and the
many town officials, both of Arlington and Lexington, who assisted us
in this study. We are indebted, also, to the Engineering Department
of Arlington, which took care of the operation of the Arlington Reser-
voir gaging station; the Engineering Department of Lexington which pro-
vided us maps and valuable information; the Town Planners of Arlington
and Lexington, and the voluntary observers which made the hydrological
study possible.
Very truly yours,
CAMP, DRESSER & McKEE
Darrell A. Root